Objective: Blood concentrations of eosinophils and monocytes are part of the complete blood count. Reference ranges for these concentrations during the neonatal period, established by very large sample sizes and modern methods, are needed for identifying abnormally low or high values. Study Design: We constructed reference ranges for eosinophils per l and monocytes per μl among neonates of 22 to 42 weeks of gestation, on the day of birth, and also during 28 days after birth. Data were obtained from archived electronic records over an eight and one-half-year period in a multihospital health-care system. In keeping with the reference range concept, values were excluded from neonates with a diagnosis of infection or necrotizing enterocolitis (NEC). Result: Eosinophils and monocytes per l of blood were electronically retrieved from 96 162 records, of which 63 371 that lacked a diagnosis of infection or NEC were included in this reference range report. The mean value for eosinophils per μl on the day of birth increased linearly between 22 and 42 weeks of gestation, as did the 5 and 95% values. The reference range at 40 weeks was 140 to 1300 μl -1 (mean 550 μl -1). Similarly, the mean value for monocytes increased linearly over this interval, with a reference range at 40 weeks of 300 to 3300μl -1 (mean 1400 μl -1). Over the first 4 weeks after birth, no appreciable change was observed in 5% limit and mean eosinophil count, with a slight increase in the 95% limit in week 4. A slight increase in monocyte count was observed during the first 2 weeks after birth. Conclusion: The results of this analysis describe reference ranges for blood concentrations of eosinophils and monocytes during the neonatal period. Additional study is needed for determining the relevance of values falling outside the reference range.
- reference range
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health
- Obstetrics and Gynecology